package/gerbera: fix pidfile name in start-stop-script
`NAME` is not set resulting in a pidfile without a basename:
`/var/run/.pid`. Use the correct variable `DAEMON` instead.
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>